1. Field of the Invention
This invention relates generally to methods of launching pipelines from an on-shore site into a body of water and of maintaining the pipeline above a floor of the body of water during the launching procedure.
2. Description of the Prior Art
The construction of off-shore oil or gas production facilities often requires the placement of a long pipeline on or near the ocean floor, for example, to connect a satellite well to a central producing platform.
The most common way of manufacturing the pipelines and placing them on the ocean floor is to construct the pipeline on a lay barge and to lower the constructed pipeline from the lay barge onto the ocean floor as the pipeline is constructed.
In some situations, however, it is not possible to construct the pipeline on a lay barge and simultaneously lower it onto the ocean floor because of the severe environmental conditions present. This is often the case when production facilities are being constructed in the North Sea area. Also, some flowline bundles are too complex to construct on a lay barge.
It has been proposed that an entire pipeline be constructed at an on-shore construction site and subsequently be launched from the on-shore construction site and into a body of water and then towed through the body of water to the installation site.